package reflectdemo;

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class ReflectDemo {

    //通过反射  实例化对象
    public static void reflectNewInstance() {
        Class<?> c1;
        try {
            c1 = Class.forName("reflectdemo.Student");
            Student student = (Student) c1.newInstance();

            System.out.println(student);
        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (InstantiationException e) {
            throw new RuntimeException(e);
        } catch (IllegalAccessException e) {
            throw new RuntimeException(e);
        }
    }

    //反射私有的构造方法
    public static void reflectPrivateConstructor() {
        Class<?> c1;
        try {
            c1 = Class.forName("reflectdemo.Student");

            c1.getDeclaredConstructor(String.class, int.class);

            Constructor<Student> constructor =
                    (Constructor<Student>) c1.getDeclaredConstructor(String.class, int.class);

            //设置私有的在类外可以使用
            constructor.setAccessible(true);

            Student student = constructor.newInstance("zhangsan", 18);

            System.out.println(student);
        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (NoSuchMethodException e) {
            throw new RuntimeException(e);
        } catch (InvocationTargetException e) {
            throw new RuntimeException(e);
        } catch (InstantiationException e) {
            throw new RuntimeException(e);
        } catch (IllegalAccessException e) {
            throw new RuntimeException(e);
        }
    }

    //反射私有属性
    public static void reflectPrivateField() {
        Class<?> c1;
        try {
            c1 = Class.forName("reflectdemo.Student");
            Field field = c1.getDeclaredField("name");

            //设置私有的在类外可以被修改
            field.setAccessible(true);

            Student student =(Student) c1.newInstance();

            field.set(student,"lisi");

            System.out.println(student);


        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (NoSuchFieldException e) {
            throw new RuntimeException(e);
        } catch (InstantiationException e) {
            throw new RuntimeException(e);
        } catch (IllegalAccessException e) {
            throw new RuntimeException(e);
        }
    }

    //反射私有方法
    public static void relectPrivateMethod() {
        Class<?> c1;
        try {
            c1 = Class.forName("reflectdemo.Student");
            Method method = c1.getDeclaredMethod("function", String.class);

            Student student = (Student) c1.newInstance();

            method.setAccessible(true);

            method.invoke(student,"我是一个参数");
            System.out.println(student);
        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (NoSuchMethodException e) {
            throw new RuntimeException(e);
        } catch (InstantiationException e) {
            throw new RuntimeException(e);
        } catch (IllegalAccessException e) {
            throw new RuntimeException(e);
        } catch (InvocationTargetException e) {
            throw new RuntimeException(e);
        }
    }

    public static void main(String[] args) {

        //reflectNewInstance();
        //reflectPrivateConstructor();
        //reflectPrivateField();
        relectPrivateMethod();
    }
}
